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Devillard S, Santin-janin H, Say L, Pontier D,. (2011). Linking genetic diversity and temporal fluctuations in population abundance of the introduced feral cat (Felis silvestris catus) on the Kerguelen archipelago
. 0962-1083, 20(24), 5141–5153.
Abstract: Linking temporal variations of genetic diversity, including allelic richness and heterozygosity, and spatio-temporal fluctuations in population abundance has emerged as an important tool for understanding demographic and evolutionary processes in natural populations. This so-called genetic monitoring was conducted across 12 consecutive years (19962007) at three sites for the feral cat, introduced onto the Kerguelen archipelago fifty years ago. Temporal changes in allelic richness and heterozygosity at 18 microsatellite DNA loci were compared with temporal changes in the adult population abundance index, obtained by typical demographic monitoring. No association was found at the island spatial scale, but we observed an association between genetic diversity and adult population indices from year to year within each study site. More particularly, the magnitude of successive increases or decreases in the adult population abundance index appeared to be the major factor linking the trajectories of genetic diversity and adult population abundance indices. Natal dispersal and/or local recruitment, both facilitated by high juvenile survival when the adult population size is small, is proposed as the major demographic processes contributing to such an observed pattern. Finally, we suggested avoiding the use of the harmonic mean as an estimator of long-term population size to study the relationships between demographic fluctuations and heterozygosity in populations characterized by strong multiannual density fluctuations.
Keywords: Felis silvestris catus, feral cat, genetic diversity, population abundance, temporal variation,
Programme: 279
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David Renault. (2020). A Review of the Phenotypic Traits Associated with Insect Dispersal Polymorphism, and Experimental Designs for Sorting out Resident and Disperser Phenotypes (Vol. 11). Bachelor's thesis, , .
Abstract: Dispersal represents a key life-history trait with several implications for the fitness of organisms, population dynamics and resilience, local adaptation, meta-population dynamics, range shifting, and biological invasions. Plastic and evolutionary changes of dispersal traits have been intensively studied over the past decades in entomology, in particular in wing-dimorphic insects for which literature reviews are available. Importantly, dispersal polymorphism also exists in wing-monomorphic and wingless insects, and except for butterflies, fewer syntheses are available. In this perspective, by integrating the very latest research in the fast moving field of insect dispersal ecology, this review article provides an overview of our current knowledge of dispersal polymorphism in insects. In a first part, some of the most often used experimental methodologies for the separation of dispersers and residents in wing-monomorphic and wingless insects are presented. Then, the existing knowledge on the morphological and life-history trait differences between resident and disperser phenotypes is synthetized. In a last part, the effects of range expansion on dispersal traits and performance is examined, in particular for insects from range edges and invasion fronts. Finally, some research perspectives are proposed in the last part of the review.
Keywords: fecundity hostile matrix life-history mating morphology movement range expansion reproduction wing-dimorphic wing-monomorphic
Programme: 136
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Céline Albert, Hálfdán Helgi Helgason, Maud Brault-Favrou, Gregory J. Robertson, Sébastien Descamps, Françoise Amélineau, Jóhannis Danielsen, Rune Dietz, Kyle Elliott, Kjell Einar Erikstad, Igor Eulaers, Alexey Ezhov, Michelle G. Fitzsimmons, Maria Gavrilo, Elena Golubova, David Grémillet, Scott Hatch, Nicholas P. Huffeldt, Dariusz Jakubas, Alexander Kitaysky, Yann Kolbeinsson, Yuri Krasnov, Svein-Håkon Lorentsen, Erlend Lorentzen, Mark L. Mallory, Benjamin Merkel, Flemming Ravn Merkel, William Montevecchi, Anders Mosbech, Bergur Olsen, Rachael A. Orben, Allison Patterson, Jennifer Provencher, Christine Plumejeaud, Isabeau Pratte, Tone Kristin Reiertsen, Heather Renner, Nora Rojek, Marc Romano, Hallvard Strøm, Geir Helge Systad, Akinori Takahashi, Jean-Baptiste Thiebot, Thorkell Lindberg Thórarinsson, Alexis P. Will, Katarzyna Wojczulanis-Jakubas, Paco Bustamante, Jérôme Fort. (2021). Seasonal variation of mercury contamination in Arctic seabirds: A pan-Arctic assessment (Vol. 750).
Abstract: Mercury (Hg) is a natural trace element found in high concentrations in top predators, including Arctic seabirds. Most current knowledge about Hg concentrations in Arctic seabirds relates to exposure during the summer breeding period when researchers can easily access seabirds at colonies. However, the few studies focused on winter have shown higher Hg concentrations during the non-breeding period than breeding period in several tissues. Hence, improving knowledge about Hg exposure during the non-breeding period is crucial to understanding the threats and risks encountered by these species year-round. We used feathers of nine migratory alcid species occurring at high latitudes to study bird Hg exposure during both the breeding and non-breeding periods. Overall, Hg concentrations during the non-breeding period were ~3 times higher than during the breeding period. In addition, spatial differences were apparent within and between the Atlantic and Pacific regions. While Hg concentrations during the non-breeding period were ~9 times and ~3 times higher than during the breeding period for the West and East Atlantic respectively, Hg concentrations in the Pacific during the non-breeding period were only ~1.7 times higher than during the breeding period. In addition, individual Hg concentrations during the non-breeding period for most of the seabird colonies were above 5 μg g−1 dry weight (dw), which is considered to be the threshold at which deleterious effects are observed, suggesting that some breeding populations might be vulnerable to non-breeding Hg exposure. Since wintering area locations, and migration routes may influence seasonal Hg concentrations, it is crucial to improve our knowledge about spatial ecotoxicology to fully understand the risks associated with Hg contamination in Arctic seabirds.
Keywords: Feathers Metal Polar Seasonal variation Top predators
Programme: 388
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Roquet, F.; Park, Y.-H.; Guinet, C.; Bailleul, Frdric; Charrassin, Jean-Benot. (2009). Observations of the Fawn Trough Current over the Kerguelen Plateau from instrumented elephant seals. Special Issue on Observational Studies of Oceanic Fronts, 78(3), 377–393.
Abstract: Due to its great meridional extent and relatively shallow depths, the Kerguelen Plateau constitutes a major barrier to the eastward flowing Antarctic Circumpolar Current in the Indian sector of the Southern Ocean. While most of the Antarctic Circumpolar Current transport is deflected north of the Kerguelen Islands, the remainder (~50Sv, 1Sv=106m3 s-1) must pass south of the islands, most probably through the Fawn and Princess Elizabeth Troughs. However, the paucity of finely resolved quasi-synoptic hydrographic data in this remote and infrequently sampled area has limited the progress in our knowledge of the regional circulation. Since 2004, a new approach using elephant seals from the Kerguelen Islands as autonomous oceanographic profilers has provided new information on the hydrography over the Kerguelen Plateau, covering the entire Antarctic Zone between the Polar Front and Antarctica, with a mean along-track resolution of about 25km. These finely resolved bio-logged data revealed details of a strong northeastward current found across the Fawn Trough (sill depth: 2600m; 56S, 78E). This so-called Fawn Trough Current transports cold Antarctic waters found mostly south of the Elan Bank, between the Ice Limit (58S) and the Antarctic Divergence (64S) in the eastern Enderby Basin, toward the Australian-Antarctic Basin. Our analysis also demonstrates that the Deep Western Boundary Current, which carries cold Antarctic water along the eastern flank of the southern Kerguelen Plateau collides with Fawn Trough Current at the outlet of the Fawn Trough sill. In other words, the Fawn Trough constitutes a veritable bottleneck, channelling the quasi-totality of the Antarctic Circumpolar flow found south of the Polar Front. Thanks to the unprecedented fine resolution of seal-borne data, a branch of flow centered at the Winter Water isotherm of 1C is also revealed along the northern escarpment of the Elan Bank, and then along the southern edge of Heard Island. Further analysis of different supplementary data reveals a complex circulation pattern in the entire Enderby Basin, with several distinctive branches of flow being strongly controlled by prominent topographic features such as the Southwest Indian Ridge, Conrad Rise, Elan Bank, and Kerguelen Plateau. This newly emerged frontal structure refines considerably previous large-scale circulation schematics of the area.
Keywords: Fawn Trough Current; Kerguelen Plateau [46-62S, 65-85E ]; Ocean circulation; Oceanic fronts; Southern Ocean; Bio-logging; Elephant seals
Programme: 109
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Roquet Fabien, Park Young-Hyang, Guinet Christophe, Bailleul Frdric, Charrassin Jean-Benot, . (2009). Observations of the Fawn Trough Current over the Kerguelen Plateau from instrumented elephant seals
. Journal of Marine Systems, 78(3), 377–393.
Abstract: Due to its great meridional extent and relatively shallow depths, the Kerguelen Plateau constitutes a major barrier to the eastward flowing Antarctic Circumpolar Current in the Indian sector of the Southern Ocean. While most of the Antarctic Circumpolar Current transport is deflected north of the Kerguelen Islands, the remainder (~ 50 Sv, 1 Sv = 106 m3 s- 1) must pass south of the islands, most probably through the Fawn and Princess Elizabeth Troughs. However, the paucity of finely resolved quasi-synoptic hydrographic data in this remote and infrequently sampled area has limited the progress in our knowledge of the regional circulation. Since 2004, a new approach using elephant seals from the Kerguelen Islands as autonomous oceanographic profilers has provided new information on the hydrography over the Kerguelen Plateau, covering the entire Antarctic Zone between the Polar Front and Antarctica, with a mean along-track resolution of about 25 km. These finely resolved bio-logged data revealed details of a strong northeastward current found across the Fawn Trough (sill depth: 2600 m; 56°S, 78°E). This so-called Fawn Trough Current transports cold Antarctic waters found mostly south of the Elan Bank, between the Ice Limit (58°S) and the Antarctic Divergence (64°S) in the eastern Enderby Basin, toward the Australian-Antarctic Basin. Our analysis also demonstrates that the Deep Western Boundary Current, which carries cold Antarctic water along the eastern flank of the southern Kerguelen Plateau collides with Fawn Trough Current at the outlet of the Fawn Trough sill. In other words, the Fawn Trough constitutes a veritable bottleneck, channelling the quasi-totality of the Antarctic Circumpolar flow found south of the Polar Front. Thanks to the unprecedented fine resolution of seal-borne data, a branch of flow centered at the Winter Water isotherm of 1 °C is also revealed along the northern escarpment of the Elan Bank, and then along the southern edge of Heard Island. Further analysis of different supplementary data reveals a complex circulation pattern in the entire Enderby Basin, with several distinctive branches of flow being strongly controlled by prominent topographic features such as the Southwest Indian Ridge, Conrad Rise, Elan Bank, and Kerguelen Plateau. This newly emerged frontal structure refines considerably previous large-scale circulation schematics of the area.
Keywords: Fawn Trough Current, Kerguelen Plateau [46-62S, 65-85E ], Ocean circulation, Oceanic fronts, Southern Ocean, Bio-logging, Elephant seals,
Programme: 452
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Célérier Bernard, Etchecopar Arnaud, Bergerat Françoise, Vergely Pierre, Arthaud François, Laurent Philippe, . (2012). Inferring stress from faulting: From early concepts to inverse methods
. TECTONOPHYSICS, 581, 206–219.
Abstract: We review the evolution of concepts on and methods of estimating the state of stress from fault movements. Theories of failure in isotropic materials suggested a simple geometrical construction of optimal principal stress directions from a fault plane and its associated slip. These optimal directions align shear stress and slip directions and maximize the difference between shear stress and frictional resistance on the fault plane. Optimal stress directions for calcite twinning are obtained by a similar construction, with the difference that they maximize shear stress. Force representation of seismic sources independently introduced pressure, P, and tension, T, axes at positions that also maximize shear stress on both nodal planes.
Keywords: Fault and slip, Faulting, Inverse methods, Stress,
Programme: 316
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Giraldo Carolina, Mayzaud Patrick, Tavernier Eric, Boutoute Marc, Penot Florian, Koubbi Philippe, . (2015). Lipid dynamics and trophic patterns in Pleuragramma antarctica life stages
. Antarctic Science, 27(05), 429–438.
Keywords: fatty acids, feeding patterns, ontogenetic changes,
Programme: 1142
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Massom Robert A, Giles A Barry, Fricker Helen A, Warner Roland C, Legrsy Benoit, Hyland Glenn, Young Neal, Fraser Alexander D, . (2010). Examining the interaction between multi-year landfast sea ice and the Mertz Glacier Tongue, East Antarctica: Another factor in ice sheet stability?
. J. Geophys. Res., 115(C12), C12027–.
Abstract: The Mertz Glacier tongue (MGT), East Antarctica, has a large area of multi-year fast sea ice (MYFI) attached to its eastern edge. We use various satellite data sets to study the extent, age, and thickness of the MYFI and how it interacts with the MGT. We estimate its age to be at least 25 years and its thickness to be 10–55 m; this is an order of magnitude thicker than the average regional sea-ice thickness and too thick to be formed through sea-ice growth alone. We speculate that the most plausible process for its growth after initial formation is marine (frazil) ice accretion. The satellite data provide two types of evidence for strong mechanical coupling between the two types of ice: The MYFI moves with the MGT, and persistent rifts that originate in the MGT continue to propagate for large distances into the MYFI. The area of MYFI decreased by 50% following the departure of two large tabular icebergs that acted as pinning points and protective barriers. Future MYFI extent will be affected by subsequent icebergs from the Ninnis Glacier and the imminent calving of the MGT. Fast ice is vulnerable to changing atmospheric and oceanic conditions, and its disappearance may have an influence on ice tongue/ice shelf stability. Understanding the influence of thick MYFI on floating ice tongues/ice shelves may be significant to understanding the processes that control their evolution and how these respond to climate change, and thus to predicting the future of the Antarctic Ice Sheet.
Keywords: fast ice, ice sheet, interaction, 0776 Cryosphere: Glaciology, 0750 Cryosphere: Sea ice, 0728 Cryosphere: Ice shelves, 0732 Cryosphere: Icebergs,
Programme: 1050
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Petra Quillfeldt, Yoshan Moodley, Henri Weimerskirch, Yves Cherel, Karine Delord, Richard A. Phillips, Joan Navarro, Luciano Calderón, Juan F. Masello. (2017). Does genetic structure reflect differences in non-breeding movements? A case study in small, highly mobile seabirds (Vol. 17).
Abstract: In seabirds, the extent of population genetic and phylogeographic structure varies extensively among species. Genetic structure is lacking in some species, but present in others despite the absence of obvious physical barriers (landmarks), suggesting that other mechanisms restrict gene flow. It has been proposed that the extent of genetic structure in seabirds is best explained by relative overlap in non-breeding distributions of birds from different populations. We used results from the analysis of microsatellite DNA variation and geolocation (tracking) data to test this hypothesis. We studied three small (130–200 g), very abundant, zooplanktivorous petrels (Procellariiformes, Aves), each sampled at two breeding populations that were widely separated (Atlantic and Indian Ocean sectors of the Southern Ocean) but differed in the degree of overlap in non-breeding distributions; the wintering areas of the two Antarctic prion (Pachyptila desolata) populations are separated by over 5000 km, whereas those of the blue petrels (Halobaena caerulea) and thin-billed prions (P. belcheri) show considerable overlap. Therefore, we expected the breeding populations of blue petrels and thin-billed prions to show high connectivity despite their geographical distance, and those of Antarctic prions to be genetically differentiated.
Keywords: Falkland / Malvinas Islands Genetic structure Kerguelen Islands Non-breeding distribution Phylogeography Procellariidae South Georgia Spatial distribution
Programme: 109
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Philip L. Woodworth. (2022). Advances in the observation and understanding of changes in sea level and tides (Vol. 1516).
Abstract: Climate change, of which sea level change is one component, is seldom out of the news. This paper reviews developments in the measurement and understanding of changes in sea level and tides, focusing on the changes during the past century. The main aim has been to demonstrate how sea level and tidal science are now connected intimately with the fields of climate change and geodesy.
Keywords: extreme sea levels MSL changes ocean circulation variability ocean tides and their changes sea level and geodesy vertical land movements
Programme: 688
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